Flow control valve



' chamber. Subsequently,

United States Patent Ofiice 3,376,889 Patented Apr. 9, 1968 3,376,889FLOW CONTROL VALVE Aladar 0. Simko, Detroit, Mich., assignor to FordMotor Company, Dearborn, Mich., a corporation of Delaware Filed Apr. 20,1964, Ser. No. 361,199 6 Claims. (Cl. 137540) This invention relates toa fuel injection system. More particularly, it relates to theconstruction of a delivery valve for controlling the flow between a pumpand an injection nozzle not only to limit the backflow of fuel into thesystem after each pump stroke, but also to reduce the residual pressurein the nozzle delivery line.

The known fuel injection pumps of the type to which the invention isdirected generally have a number of reciprocating plungers eachintermittently delivering a charge of fuel past a delivery valve to aninjection nozzle. The delivery valve is provided for a number ofreasons. One is to limit the amount of fuel backfiow into the pumppressure chamber so that if an air pocket is trapped in the highpressure line, it can be driven out on successive pressure strokes ofthe pump plungers. Otherwise, the air pocket would expand during thedecrease in pump pressure, and would not be driven out of the deliveryline. In any practical case, one delivery cycle does not displace enoughfuel past the injection nozzle to compress the air pocket to the openingpressure of the nozzle.

A second reason for the provision of the delivery valve is to reduce theresidual pressure in the high pressure delivery line after each strokeof the pump plunger. This prevents secondary injection due toreverberation of pressure waves in the closed high pressure line whensuperimposed on high residual pressure.

The above functions generally are accomplished by constructing thedelivery valve to retract a finite or predetermined small volume of itsmass out of the high pressure delivery'line during the non-pressurestroke of the pump plunger. That is, expand the high pressure line by afinite amount. There is a basic difiiculty, however, with such aconstruction. Separate delivery valves are required for each injectionnozzle and pump plunger, and since a typical system may have six or moredelivery valves, each of the valves must be manufactured to extremelyclose tolerances so that each of the valves will always retract the sameprecise volume. Without such control, the delivery through each of thenozzles might be quite different even though the pump plungers deliverthe same quantity of fuel. An unbalanced situation would result whereineach of the nozzles delivered a different quantity of fuel, therebyrequiring considerable adjustment and maintenance for the engine to runefiiciently. This poses both manufacturing and wear problems, therefore.

The invention eliminates these disadvantages by separating the twofunctions of the delivery valve. The delivery valve of the inventionincludes a pressure sensitive diaphragm valve that seats immediatelyafter the pump stroke to cut off return flow of fuel into the pumppressure the residual pressure in the injector delivery line is reducedby expanding the volume of the line. That is, the high pressure in thedelivery line balloons the diaphragm until one of two conditions occurs;either the pressure forces on opposite sides of the diaphragm becomebalanced; or, the internal expansion reaches a predetermined maximum. Asto this last condition, a control is provided that permits an internalexpansion beyond that needed for air-free operation, but less than thevolume of fuel to be injected during each pumping stroke of theplungers.

It is an object of the invention, therefore, to provide a unidirectionalflow valve assembly for controlling the flow of fluid between twovarying pressure lines that not only controls the return flow of fuel,but reduces the residual pressure in one line until the pressure forceson opposite sides of the valve are in equilibrium or balanced.

It is a further object of the invention to provide a delivery valve forcontrolling the flow of fuel between a fuel injection pump and nozzle,the valve including a pressure sensitive diaphragm valve element thatseats upon a drop in the inlet line pressure to block return fuel flow;the diaphragm subsequently moving in response to the residual pressurein the delivery line to increase the internal volume of the deliveryline until one of two conditions is met; either the pressure forcesacting on opposite sides of the diaphragm become balanced; or, theincrease in internal volume reaches a predetermined maximum.

It is a further object of the invention to construct'a fuel injectionsystem delivery valve with a pressure sensitive diaphragm that permits acontinuous expansion of the internal volume of the delivery linesubsequent to the seating of the valve to block return flow from theline 'to the pump internal system.

A still further object of the invention is to provide a fuel injectionsystem delivery valve that is simple in construction, economical tomanufacture, and operates in an efficient manner.

Other objects, features, and advantages of the invention will becomeapparent upon reference to the succeeding, detailed description thereof,and to the drawings illustrating a preferred embodiment thereof;wherein,

FIGURE 1 shows a portion of a fuel injection system incorporating aknown type of delivery valve; and,

FIGURES 2, 3, 4 andS are cross-sectional views of a delivery valveconstructed according to the invention and illustrated during successivephases of operation in the successive figures.

FIGURE 1, which is essentially to scale, shows'a portion of a known fuelinjection apparatus. It has a housing 10, the lower portion of whichrotatably supports a shaft 12 that is driven, for example, by thecamshaft of an internal combustion engine. A wobble plate 14, having acam surface 15, is fixed to the end of shaft 12, as is the lower end ofa rotary valve 16. The valve rotates within a bore 18 in housinglO, andis formed with suitable spaced lands 20 and 22. The lands are connectedby a reduced neck portion 24 providing an annular fuel chamber 26. Thevalve ocntrols the flow of fuel between an inlet line 28 and a bore 30in a known manner; that is, it has a flow cutoff portion 32 forprogressively blocking or opening the connections and controllingspillage of fuel from bore 30 back into chamber 26.

Wobble plate 14 slidably supports a number (only one shown) ofnon-rotating spaced slipper elements 34, the number varying with thedesign of the pump. Each of the slippers has a cup-shaped recess 36receiving the spherical end 38 of a tappet 40 enclosing one end of apump plunger 42. The tappet has a sliding sealed fit within a bore 43 inhousing 10, its upper radial movement being terminated by abutmentagainst a stop plate 46. The stop plate is seated on a stepped portion48 in housing 10, and is apertured for slidably receiving the stem orneck portion 50 of plunger 42. The plunger has a spherical .portion 52at its tappet end, and a cylindrical piston-like portion 54 at theopposite end. The piston portion slides in the lower portion of a bore56 having an upper compression chamber portion 58 opening directly intoa chamber 60 in the cover portion of housing 10. The flow between thetwo chambers is controlled by a spring seated nonreturn flow deliveryvalve 62 of a known construction. The chamber 58 is intersected by thecross bore 30 that is closed at one end by plug 64.

Plunger 42 is based to its bottom dead center position by a spring 66that surrounds stem 50 and is seated between plate 46 and the plungerend 52.

In operation, rotation of drive shaft 12 rotates cam plate 14 to forceplunger 42 upwardly through its compression or pumping stroke, whilepermitting it to descend through its suction stroke under the force ofspring 66. During the suction stroke, fuel is drawn into bore portion 58from bore 30, rotary valve 16 at this time connecting line 28 and bore30. During the first part of the up-stroke of plunger 42, the rotaryvalve cutoff portion 32 maintains bore 30 open, and fuel spills frombore portion 58 back through bore 30. Actual delivery of fuel pastdelivery valve 62 takes place during the mid-portion of the plungerstroke when the rotary valve cutoff 32 has moved to a position closingbore 30. When this occurs, continued upward movement of plunger 42compresses the fuel in bore 58 and causes valve 62 to be lifted off itsseat, so that a high pressure charge of fuel is injected into line 72and out through injector 74. During the final portion of the plungerpumping stroke, the rotary valve cutoff portion 32 will uncover bore 30and permit spillage of fuel back into the valve chamber 26. This willcontinue until the plunger piston portion 54 reaches its top dead centerposition. Thus, it will be seen that the rotary motion of drive shaft 12will reciprocate each of the plunger pistons in timed relationship, and,therefore, intermittently inject charges of fuel into chamber 60.

The delivery valve 62, as stated previously, is a check or non-returnflow type valve; that is, it moves out of bore portion 58 in response tothe fuel pressure in the bore during the ascending compression stroke ofthe plunger, the fuel being discharged past the valve into delivery line72. The injector nozzle 74 is of a known construction, and its details,therefore, are not given. It remains closed below a predeterminedinjection pressure. The charge of fuel that is discharged into line 72,therefore, rises in pressure up to the injector opening pressure, atwhich point a predetermined volume of fuel is injected from the nozzleinto the engine combustion chamber, not shown.

The discharge valve 62 shown in FIGURE 1 represents a known poppet-typevalve. It has a generally conical upper land 76 joined to a spacedcylindrical land 78 by a reduced diameter neck portion 80. The conicalland 76 is adapted to seat against a mating tapered surface 88 formed inthe upper portion of pump housing 10. The valve has a lower guideportion 86 that is fluted or slotted so that fuel in bore portion 58 canact on the underside of land 78. The valve is biased to its seated flowblocking position by a spring 90.

During the last part of the compression stroke of plunger 42, rotaryvalve 16 attains a position permitting spillage of fuel brom boreportion 58 back into bore 30. The pressure in bore 58 then drops and thespring 90 and higher pressure in line 72 causes the land 78 of valve 62to begin to enter the cylindrical portion of bore 58. As soon as thelower edge of land 78 contacts the bore wall, fuel flow between boreportion 58 and chamber 60 becomes blocked. At this moment, the pressurein line 72 is substantially equal to the nozzle injection closingpressure. However, the valve continues its downward movement until theconical land 76 seats on the surface 88; this continued movementretracts a definite area or volume of the valve into the bore 58 and outof the chamber 60. The volume of chamber 60, therefore, is increased,and the residual pressure in line 72 and chamber 60 is thereby reducedby the finite amount defined by the movement of land 78 into bore 58.

As discussed previously, a delivery valve such as valve 62, operates onthe principle of retracting a finite volume during the suction stroke ofthe pump plunger. This is disadvantageous because of the close tolerancerequirements necessary during manufacture of the valve so that all ofthe valves of the pump assembly will retract exactly the same volume.

A simpler delivery valve constructed according to the invention is shownin FIGURES 2 through 5. FIGURE 2 shows the pump housing 10 having arecessed portion providing a T-shaped chamber 100. The chamber isconnected at one end to the fuel delivery line 72, and faces a smallerdiameter T-shaped chamber 102 connected to bore portion 58. The deliveryvalve comprises a flexible annular rubber or other suitably constructeddiaphragm 104 positioned between thin fiat discs 106 and 108. Disc 106has a smaller diameter than the recess 110 so as to be radially movablewithin it, in a manner to be described. A spring 112 biases the disc 110against diaphragm 104. larger force spring 114 biases disc 106 againstthe d1- aphragm to sealingly seat the diaphragm edges against the valvebody and thereby block flow between bore portion 58 and line 72. Disc106 has a restricted opening 118 permitting the fuel in delivery line 72to act on the upper portion 122 of the diaphragm. The underside 124 ofthe diaphragm is acted upon by the fuel in bore portion 58.

It will be clear from the above that fuel delivery Will begin when thevalve 16 has rotated to block spillage back through bore 30 and causethe fuel pressure to build up in bore portion 58. When the combinedforces of spring 112 and the fluid pressure in bore portion 58, actingon the disc 108 and underside 124 of the diaphragm, are greater than theforces due to spring 114 and the pressure in line 72 acting through hole118 on the diaphragm, the fuel in bore portion 58 will move diaphragm104 and disc 108 upwardly away from the flat valve body seat 126 topermit flow into chamber around the edges of the valve. The pressure inline 72 will then be sufficient to open the nozzle 74, and a charge offuel will be ejected. This condition of operation is shown in FIG- URE3.

When control valve 16 rotates to a position unblocking bore 30 duringthe last portion of the compression stroke of the pump plunger, therebypermitting spillage of fuel from bore portion 58, the pressure in boreportion 58 will decrease to a level lower than the combined forces ofspring 114 and the residual pressure in line 72. The injector willclose, and diaphragm 104 and discs 106 and 108 will then return to thepositions shown in FIGURE 2, cutting off flow between line 72 and boreportion 58. At this point, the residual pressure in line 72 issubstantially equal to the injection nozzle closing pressure. Uponcontinued decrease in the pump pressure in bore portion 58, the higherresidual fluid pressure force acting through hole 118 on the upper partof the diaphragm will force the central portion of the diaphragm toballoon downwardly into the recess 110, as illustrated in FIGURE 4. Thisprovides an expansion or increase in the internal volume of chamber 100,and, therefore, decreases the residual pressure in line 72. Thisdownward movement of the diaphragm will continue until the combinedforces acting against the opposite sides of the diaphragm are balanced.Thus, it will be seen that the delivery valve is capable of providing avariable increase in the internal volume of chamber 100, and one that isproportionate to the decrease in pressure on the inlet side of thevalve.

The recess is provided with a beveled or tapered edge 128 and a step 130that act as stops for the downward movement of the diaphragm. Theyassure that the delivery valve will not increase the volume in chamber100 by an amount greater than the maximum displacement of fuel duringany one upstroke of the pump plunger. That is, the diaphragm can movedownwardly as long as the disc 110 and the edges of the diaphragm arefree to move. Once they rest against the edge 128 and shoulder 130,further expansion of the internal volume of chamber 100 and line 72 isprevented. This particular condition is illustrated in FIGURE 5. Thisassures that some fuel will be forced into line 72 during every deliverycycle, so that the pressure of any air pocket that initially may bepresent in line 72 will gradually rise to the opening pressure of nozzle74, and be driven out.

Thus, it will be seen that the delivery valve performs two functions.First the diaphragm valve seats on surface 126 to block return flow offuel from line 72 to the pressure chamber 53. Secondly, the centralportion of diaphragm 106 is forced downwardly, progressively increasingthe internal volume of chamber 100 and decreasing the residual pressurein line 72. This will continue until the pressure forces on oppositesides of the diaphragm are balanced, as shown in FIGURE 4, or until themovement has continued up to the permissible predetermined maximumincrease in the internal volume of chamber 100, at which point thediaphragm will be in the position shown in FIGURE 5.

The pumping phase of operation is accomplished in the reverse manner;that is, the higher combined forces acting on the underside of thediaphragm move it progressively through the phases from the positionsindicated in either FIGURES 5 or 4 to FIGURE 2, and then to the positionillustrated in FIGURE 3, at which point flow is permitted between thebore 58 and delivery line 72.

From the foregoing, it will be seen that the invention provides a flowcontrol valve that permits flow in one direction while preventing returnflow, and subsequently reduces the residual pressure on the deliveryside of the valve by an expansion or increase in the internal volume ofthe delivery line. The invention also provides a construction thatforces air pockets out of the system and assures a delivery of fuelduring each delivery cycle.

The invention further assures equal delivery through each nozzle bymaintaining a near equal volume for every high pressure line-nozzleassembly, and equal force springs acting on the inlet sides of thediaphragms. Since the fuel has a very high modulus of elasticity, slightvariations in the delivery line volume and the residual pressure of thefluid therein between different assemblies will result only innegligible variations in volume delivered through the nozzle with equaldelivery from the plungers.

While the invention has been illustrated in connection with a fuelinjection system, it will be clear to those skilled in the arts to whichthe invention pertains that it would have use in other installations,and that many changes and modifications may be made thereto withoutdeparting from the scope of the invention.

1. Fluid flow control means comprising, a fluid inlet line containing afluid that varies in pressure, a fluid discharge line having meanstherein blocking its outlet below a predetermined pressure of fluidtherein, and unidirectional flow control valve means between said inletline and the inlet to said discharge line and movable in response todifferential fluid pressure forces between said lines acting in one andthe opposite directions to communicate or block, respectively, flowbetween said lines, said valve means having control means movable inresponse to a differential fluid pressure force acting in the oppositedirection to block said flow and balance the pressures in said lines,said valve means comprising a valve bore connecting said lines andhaving a valve seat therein, a diaphragm in said bore adapted to engagesaid seat to block flow between said lines, a valve member adapted tooverlay said diaphragm, means biasing said valve member and diaphragmagainst said seat to block the said flow, said valve member having anaperture therein admitting fluid from said discharge line to act on oneside of said diaphragm, said diaphragm being acted upon on its oppositeside by the fluid in said inlet line, said discharge line fluidballooning a portion of said diaphragm to increase the volume anddecrease the pressure in said discharge line until the fluid pressureforces on opposite sides of said diaphragm are balanced, and meansoperable above a predetermined differential in said fluid pressureforces to limit ballooning of said diaphragm.

2. Fluid flow control means comprising, a fluid inlet line containing afluid that varies in pressure, a fluid discharge line having meanstherein blocking below a predetermined pressure of fluid therein, andunidirectional flow control valve means between said inlet line and theinlet to said discharge line and movable in response to difl erentialfluid pressure forces bet-ween said lines acting in one and the oppositedirections to communicate or block, respectively, flow between saidlines, said valve means having control means movable in response to adifferential fluid pressure force acting in the opposite direction toblock said flow and balance the pressures in said lines, said valvemeans comprising a valve bore connecting said lines and having a valveseat therein, a diaphragm in said bore adapted to engage said seat toblock flow between said lines, a valve member adapted to overlay saiddiaphragm, means biasing said valve member and diaphragm against saidseat to block the said flow, said valve member having an aperturetherein admitting fluid from said discharge line to act on one side ofsaid diaphragm, said diaphragm being acted upon on its opposite side bythe fluid in said inlet line, said discharge line fluid ballooning aportion of said diaphragm to increase the volume and decrease thepressure in said discharge line until the fluid pressure forces onopposite sides of said diaphragm are balanced, or until the dischargeline volume has increased a predetermined amount, and means operableabove a predetermined differential in said fluid pressure forces tolimit ballooning of said diaphragm.

3. Fluid flow control means comprising, a fluid inlet line containing afluid that varies in pressure, a fluid discharge line having meanstherein blocking its outlet below a predetermined pressure of fluidtherein, and unidirectional flow control valve means between said inletline and the inlet to said discharge line and movable in response todifferential fluid pressure forces between said lines acting in oneandthe opposite directions to communicate or block, respectively, flowbetween said lines, said valve means having control means movable inresponse to a differential fluid pressure force acting in the oppositedirection to block said flow and balance the pressures in said lines,said valve means comprising a valve bore connecting said lines andhaving a valve seat therein, a diaphragm in said bore adapted to engagesaid seat to block flow between said lines, a valve member adapted tooverlay said diaphragm, means biasing said valve member and diaphragmagainst said seat to block the said flow, said valve member having anaperture therein admitting fluid from said discharge line to act on oneside of said diaphragm, said diaphragm being acted upon on its oppositeside by the fluid in said inlet line, said discharge line fluidballooning a portion of said diaphragm to increase the volume anddecrease the pressure in said discharge line by a predetermined amount,and means operable above a predetermined differential in said fluidpressure forces to limit ballooning of said diaphragm.

4. Fluid flow control means comprising, a fluid inlet line having avalve seat and containing a fluid that varies in pressure, a fluidoutlet line connected to said inlet line and means therein normally adischarge portion below a predetermined pressure of the fluid therein,and unidirectional flow control valve means between said lines movableaway from or against said valve seat by and in response to differentialfluid pressure forces between said lines resulting from changes in thefluid pressure in said inlet line, said differential forces acting onsaid valve means in one and the opposite directions to communicate orblock, respectively, flow bet-ween said lines, said valve means havingflexible control means movable first against said valve seat in responseto a differential fluid pressure force acting in the opposite directionresulting from a lowering of the pressure in said inlet line below thesaid predetermined fluid pressure level at which said outlet line isblocked to block said flow and subsequently being deformed towards saidinlet line in response to a predetermined rise in said differentialforce, and means operable above a predetermined pressure of the fluid insaid outlet line to limit the movement of said control means toward saidinlet.

5. Fluid flow control means comprising, a fluid inlet line having avalve seat and containing a fluid that varies in pressure, a fluidoutlet line connected to said inlet line and means therein normally adischarge portion below a predetermined pressure of the fluid therein todefine a chamber of a predetermined volume in said line, and non-returnflow valve means between said lines movable away from or against saidvalve seat by and in response to differential fluid pressure forcesbetween said lines resulting from a lowering of the pressure in saidinlet line below the said predetermined fluid pressure level at whichsaid outlet line is blocked acting on said valve means in one and theopposite directions to communicate or block, respectively, flow betweensaid lines, said valve means having flexible control means movable firstagainst said valve seat in response to a differential fluid pressureforce acting in the opposite direction resulting from a lowering of thepressure in said inlet line below the said predetermined fluid pressurelevel at which said outlet line is blocked to block said flow andsubsequently being deformed towards said inlet line in response to apredetermined use in said differential force to increase the volume andreduce the residual pressure in said chamber, and means to limit themovement of said control means toward said inlet above a predeterminedincrease in volume of said chamber.

6. A delivery valve assembly comprising, a valve bore having a seattherein, fluid inlet and outlet lines connected to different portions ofsaid bore, means for intermittently delivering fluid under pressure tosaid inlet line whereby the pressure of the fluid therein alternatelyrises and falls with the delivery or non-delivery of fluid thereto,means blocking the discharge of fluid from said outlet line below apredetermined fluid pressure therein, and non-return valve means in saidbore for controlling the flow between said lines, said valve means beingmovable in response to a predetermined differential fluid pressure forcebetween said lines resulting from changes in the fluid pressure in saidinlet line, said differential forces acting in one direction on saidvalve means to permit flow between said lines and seatable to block flowbetween said lines upon a pressure differential between said linesacting in the opposite direction, said valve means including a pressuresensitive diaphragm valve, means biasing said valve against said seat toblock said flow, said valve being differentially acted upon by thepressures of the fluid in said lines and responsive to a diflerentialbetween said line pressures acting in said opposite direction resultingfrom a lowering of the pressure in said inlet line below the saidpredetermined fluid pressure level at which said outlet line is blockedfor ballooning of said diaphragm to a shape reducing the residualpressure in said outlet line subsequent to the seating of said valve,and means operable above a predetermined residual pressure in saidoutlet line to limit movement of said diaphragm toward said inlet.

References Cited UNITED STATES PATENTS 2,959,188 11/ 1960 Kepner 1375403,025,874 3/1962 Yucum 137540 2,121,102 6/1938 Scott 2395 2,922,5811/1960 Garday 2395 2,467,635 4/ 1949 Sozorka 137540 2,635,630 4/1953Cornelius 137540 X 2,670,759 3/1954 St. Clair 137540 2,789,578 4/1957Goepfrick 137540 X 2,949,930 8/1960 Moore 1375l6.29

WILLIAM F. ODEA, Primary Examiner.

D. LAMBERT, Assistant Examiner.

1. FLUID FLOW CONTROL MEANS COMPRISING, A FLUID INLET LINE CONTAINING AFLUID THAT VARIES IN PRESSURE, A FLUID DISCHARGE LINE HAVING MEANSTHEREIN BLOCKING ITS OUTLET BELOW A PREDETERMINED PRESSURE OF FLUIDTHEREIN, AND UNIDIRECTIONAL FLOW CONTROL VALVE MEANS BETWEEN SAID INLETLINE AND THE INLET TO SAID DISCHARGE LINE AND MOVABLE IN RESPONSE TODIFFERENTIAL FLUID PRESSURE FORCES BETWEEN SAID LINES ACTING IN ONE ANDTHE OPPOSITE DIRECTIONS TO COMMUNICATE OR BLOCK, RESPECTIVELY, FLOWBETWEEN SAID LINES, SAID VALVE MEANS HAVING CONTROL MEANS MOVABLE INRESPONSE TO A DIFFERENTIAL FLUID PRESSURE FORCE ACTING IN THE OPPOSITEDIRECTION TO BLOCK SAID FLOW AND BALANCE THE PRESSURES IN SAID LINES,SAID VALVE MEANS COMPRISING A VALVE BORE CONNECTING SAID LINES ANDHAVING A VALVE SEAT THEREIN, A DIAPHRAGM IN SAID BORE ADAPTED TO ENGAGESAID SEAT TO BLOCK FLOW BETWEEN SAID LINES, A VALVE MEMBER ADAPTED TOOVERLAY SAID DIAPHRAGM, MEANS BIASING SAID VALVE MEMBER AND DIAPHRAGMAGAINST SAID SEAT TO BLOCK THE SAID FLOW, SAID VALVE MEMBER HAVING ANAPERTURE THEREIN ADMITTING FLUID FROM SAID DISCHARGE LINE TO ACT ON ONESIDE OF SAID DIAPHRAGM, SAID DIAPHRAGM BEING ACTED UPON ON ITS OPPOSITESIDE BY THE FLUID IN SAID INLET LINE, SAID DISCHARGE LINE FLUIDBALLOONING A PORTION OF SAID DIAPHRAGM TO INCREASE THE VOLUME ANDDECREASE THE PRESSURE IN SAID DISCHARGE LINE UNTIL THE FLUID PRESSUREFORCES ON OPPOSITE SIDES OF SAID DIAPHRAGM ARE BALANCED, AND MEANSOPERABLE ABOVE A PREDETERMINED DIFFERENTIAL IN SAID FLUID PRESSUREFORCES TO LIMIT BALLOONING OF SAID DIAPHRAGM.